The brown recluse spider is a species of spider known for its particularly venomous bite. Despite normally being native to the southwestern United States,[1]Hogwarts Castle had a significant population of the creatures.[2]

Behind the scenes

Oddly, despite being well known in real life for their poison, as well as the Folio Bruti calling them "particularly venomous", the brown recluse is not capable of inflicting the poison status.